This invention relates generally to a closure assembly for evacuated blood collection tubes such as VACUTAINER .RTM. Brand evacuated tubes. More particularly, this invention relates to such a closure which reduces the incidence of contamination of the user of the evacuated tube when obtaining a blood sample from the tube.
As is well known in the medical field, evacuated tubes are used in large quantities to take blood samples from patients for subsequent testing of the blood for various purposes to determine if a patient has certain diseases or blood problems or other physical health problems of some kind. It is routine for a laboratory technician, for example, to take several samples from a single evacuated tube for various tests. Since the tube is evacuated, there is a pressure differential across the stopper holding the sample in the tube many times. Thus, when a needle is inserted through the diaphragm of the stopper, there can be an aerosol of the sample which may spray onto the technician. Moreover, when taking samples, sometimes blood droplets are left on the top surface of the stopper during the removal of the needle once a sample has been taken from the evacuated tube.
Thus, there is an exposure problem to the user of such evacuated tubes containing blood samples of contamination from a blood sample which may be a diseased blood sample of some kind.
With this invention, by contrast, an arrangement is provided for reducing to a minimum exposure of aerosol or blood droplets which may be evident in removing a blood sample from an evacuated tube. This is achieved by providing a cap assembly which is mounted over the resilient rubber stopper of the evacuated tube. The internal surface of the cap is configured to provide opposing abutments which cooperate with the portion of the rubber stopper extending from the evacuated tube in order to hold the cap in place. The cap includes a top portion which extends over the top of the stopper to define between the top surface of the stopper and the bottom surface of the extended top portion of the cap a cavity which serves to contain any blood droplets or aerosol which may arise when a sample is removed from the tube. The top portion extending over the top surface of the stopper includes a central bore for receiving the needle necessary for puncture of the diaphragm for removing the sample. Otherwise, the top surface of the stopper is effectively closed so as to, as discussed above, contain any aerosol or blood droplets which may arise from taking the sample.
With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.